*ngif else if in template

javascript

prompt-engineering

best-practices

web-development

byAlex Kataev·Sep 26, 2024

Quickly implement a "mock else if" logic in Angular using *ngIf tied with else blocks linked with template references:

<ng-container *ngIf="condition1; else condition2Ref">
  <!-- When life gives you condition1... -->
</ng-container>

<ng-template #condition2Ref>
  <ng-container *ngIf="condition2; else condition3Ref">
    <!-- Squeeze the best out of condition2 -->
  </ng-container>
</ng-template>

<ng-template #condition3Ref>
  <!-- Or sip on condition3 instead -->
</ng-template>

Use <ng-container> for conditional checks and <ng-template> armed with unique reference variables (#condition2Ref, #condition3Ref) to handle the sequential rendering flow, creating "else if" conduct.

Understanding Nesting ngIf & its quirks

Angular's conditional rendering is like directing a busy spin-off Star Trek: you need to efficiently manage a plethora of conditions without disrupting the flow. That's where *ngIf with else, <ng-container>, and <ng-template> beam in to save the galaxy.

The Ternary Zing: A quick solution

In some scenarios, a less verbose and more compact approach — ternary operators may seem appealing. These are especially handy when dealing with simple content changes based on conditions:

<div>
  {{ condition1 ? 'First Officer Spock' : (condition2 ? 'Captain Kirk' : 'Scotty, beam us up!') }}
</div>

Now you've got a compact code, but remember, it can turn into an alien language when dealing with complex logic. Don't let your logic become Klingon!

Simulating else-if structures: An Angular Pretend-play

While Angular doesn't directly support the else-if directive, worry not! You can simulate this behavior by nesting *ngIf directives. Always use <ng-container> whenever you need an invisible wrapper and want to avoid any extra-terrestrial DOM elements.

The ngSwitch Tactic: For the Multi-Value Scenarios

In scenarios where your variable is as unpredictable as the tribbles, ngSwitch performs well. However, for complex conditional trees, it might not be the most practical choice.

<ng-container [ngSwitch]="conditionValue">
  <div *ngSwitchCase="'first'">Meet Spock...🖖</div>
  <div *ngSwitchCase="'second'">Captain on the deck...</div>
  <div *ngSwitchDefault>Red alert! Shields up!</div>
</ng-container>

Flexible control with ngTemplateOutlet

For the ultimate control of your starship, Angular equips **<ng-container>** with **ngTemplateOutlet** - providing extensive flexibility for managing conditional content. It allows defining templates once and then reusing them with various conditions throughout the galaxy:

<ng-container *ngTemplateOutlet="condition1 ? template1 : condition2 ? template2 : template3"></ng-container>

<ng-template #template1>Life on Vulcan...</ng-template>
<ng-template #template2>Kobayashi Maru...</ng-template>
<ng-template #template3>Tribble alert!</ng-template>